This invention relates to access support, and in particular, but without limitation, to access support suitable for use in conjunction with both existing and new offshore installations.
An offshore installation (otherwise known as a platform) can either be manned or unmanned but, in both instances, routine maintenance needs to be carried out from time to time. In order to achieve this, it is necessary to man the platform and lift equipment & supplies onto the platform and this can be accomplished, in most cases, by a crane that is already mounted on the platform. However, in the case where the platform is unmanned, crane usage is infrequent, it becomes degraded over time, due to corrosion, fatigue and exposure to the elements and obsolescence issues cause failures. As such, before any maintenance and/or repair work can take place on the platform, it is often necessary to re-commission the crane prior to work commencing.
In order to achieve this, it is therefore necessary to air-lift crewmembers onto the platform using a helicopter, which is a hazardous activity. In addition, flying a crew onto the platform is very expensive.
In situations where the crew are required to maintain and/or upgrade a normally unmanned platform, it is also necessary to provide life-support on the platform in case of an emergency. For example, if the weather and/or the conditions are such that the crew cannot be evacuated by sea or air, it is necessary for them to be able to live safely on-board the platform, even if only for a short period of time. Whilst the platform may be supported whilst the crew are on the platform by a standby support vessel and/or a lifeboat system, it is generally not possible to leave crewmembers on an otherwise unmanned platform for extended periods of time.
With the passage of time, the platform degrades further, eventually leading to a situation where the required maintenance and remedial work exceeds the capabilities of helicopter intervention.
One known solution to this problem is to lift onto the platform temporary living accommodation units, which comprises sleeping quarters, messing facilities, first aid, and office space, etc., but this requires the use of an operational crane and if the crane is not serviceable, then alternative solutions need to be found. In addition, locating these temporary living accommodation units on a producing platform can result in unacceptable risks to personnel. These risks can only be mitigated by shutting down production and this will result in a major loss of revenue. This invention aims to locate the temporary living accommodation away from any hydrocarbon production areas and can incorporate blast and fire protection, which can significantly reduce the risk to personnel.
It is known, in such circumstances, to use a so-called “jack up”, which is a rig that can be floated out to the platform and located close by, whereupon legs can be extended downwardly from the jack-up until they rest on the seabed. Further jacking thereby raises the jack-up above the water level providing a temporary structure adjacent the main platform, which can be used for providing the necessary life-support services, equipment and storage space that, is needed for the operators on-board the platform. However, a jack-up is extremely expensive to use and therefore a need exists for an alternative type of support structure, in particular for an offshore platform.
It is also known to provide an accommodation support vessel (ASV) adjacent the main platform with a bridge connector, which can be anchored to the platform. However, these ASVs also involve the use of a jack-up for crane installation (albeit for a shorter period of time than if the jack-up were to be used, itself, as the support structure) and this, of course, introduces additional cost and complexity to the procedure.
A further consideration is that all of the above solutions rely on helicopter access and this significantly increases the risk to personnel when compared with marine access solutions. However, to date, these marine access solutions have been unable to provide a method of safely docking and remaining on station.
The invention therefore aims to provide a solution to one or more of the above problems and/or to provide an improved and/or alternative support structure for use when working on, or servicing, an offshore platform.
The invention may also provide a solution, which reduces the risk to personnel whilst addressing one or more of the above problems: the combination of remote temporary living accommodation and marine access may result in a major reduction in the risk to personnel and may facilitate further safety improvements.
Various aspects of the invention are set forth in the appendent claims.